Damaging caterpillars of the PNW: updates and information

Winter Cutworm Update

Winter cutworm is a new pest threat in this region. It has a wide host range and can be very destructive because it moves and feeds in large masses, similar to armyworms. As the name implies, cutworms are active during the winter, and therefore can affect perennial and fall-seeded crops including legume and grass cover crops, grasses grown for seed, ornamentals, vegetables, and grains.

Between November 2015 and February 2016, dozens of reports were made throughout Oregon and Washington, where there was suspected damage from winter cutworm, which is the immature, damaging stage of the large yellow underwing moth. Adult moths have been present in this region since 2001, yet there had never before been accounts of widespread damage being done by winter cutworm. In response, an OSU Extension publication was released (availablehere), and public presentations were made in Multnomah, Polk, Linn, Benton, and Douglas counties.

Large Yellow Underwing moths can be recognized by the distinct pattern and coloration on the hindwing. Photo credit: Merrill Peterson

Adult moths have been very abundant over the past few weeks. They are easily recognizable by their large size (~2″) and hindwing, which is bright orange-yellow and bordered by a thick dark band.

We are currently researching whether winter cutworm will be a problem again in the months to come.

2 thoughts on “Winter Cutworm Update”

Thanks for the info! Effects of this moth are still very uncertain, so I appreciate any and all reports of activity/sightings. Keep your eye out, as another flight period begins in August, and extends into October. Thanks again!
Jessica

We live in Northwest McMinnville and have seen several of these moths this summer and last summer. As many as 15 (likely more) came into a glass- enclosed sunroom attached to our house last year. Over the winter I found two of the cutworms and another this spring. This summer there have been fewer moths so far — maybe 6 that got into our covered porches. We planted red clover and eye grass cover crops in our backyard garden. Bad didn’t notice damage to them.